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North Norfolk SMP2 - H i - Appendix H – Economic appraisal Final plan October 2010

Appendix H

Economic appraisal

North Norfolk SMP2 - H ii - Appendix H – Economic appraisal Final plan October 2010

Appendix H Contents

Page

H1 Introduction 1

H2 Method 1 H2.1 Data sources 1 H2.2 Assumptions 3 H2.3 Conclusions about viability 4

H3 Analysis 4

H4 References 11 List of tables H2.1 Estimated defence costs 3 H2.2 Estimated future defence costs 3 H1 Economic assessment summary for each policy development zone 12 H2 Economic assessment summary for each super-frontage 30 H3 Supporting economic data – summary table for each

policy development zone 34 H4 Supporting economic data – summary table for each super-frontage 38 H5 Supporting economic data – defence cost calculations for each policy development zone 39 H6 Supporting economic data – defence cost calculations for each super-frontage 47

North Norfolk SMP2 - H 1 - Appendix H – Economic appraisal Final plan October 2010

H1 Introduction

The task to confirm the preferred policy is split into two sub-tasks, as detailed below:

• Sensitivity testing. Identifies uncertainty in key variables and potential effects on preferred policy scenarios (see appendix E section 4.3).

• Economic viability assessment. Considers ratio of costs and benefits for preferred policy package.

This appendix reports on the economic viability task. The aim of this task is to confirm the economic viability of the preferred policy packages (PPs) by assessing the costs of flood and coastal risk management actions in relation to their economic benefits compared to a baseline of no active intervention. This involves a high-level assessment based on the approach prescribed by the Flood and Coastal Defence Project Appraisal Guidance. These policy packages have been developed for each policy development zone (PDZ). They are suites of policies for the three epochs of the SMP. They were then appraised in terms of how they perform against the defined criteria and principles (see appendices E and G). The CSG and EMF identified their preferred PPs for all PDZs based on the results of this appraisal and these have since been incorporated into the SMP. A number of the policies were then changed following public consultation. Economic viability has played a role throughout this process: it was included in the appraisal process when the draft SMP’s policies were fully assessed and reported in the draft SMP, confirming that the draft policies were viable but not by a wide margin. This appendix describes the viability of the final policies. The exact details of the preferred PPs are provided in the main SMP document, with further details in appendix E.

H2 Method

H2.1 Data sources

In line with the SMP guidance, this assessment uses the best available information about costs and benefits. If no information is available, a ‘high level assessment’ is applied, based on default defence cost data.


There is limited information for PDZ2D and PDZ3A in the existing reports listed below: • PDZ2D/2E: Brancaster West Marsh Engineers Report Final Draft

(Environment Agency 2000) • PDZ3A: Blakeney Freshes Project Appraisal Report (Halcrow 2002) For most other PDZs, default defence costs, as detailed in appendix C of the SMP guidance (Defra 2006), have been compared to approximate values of residential properties as provided by the National Properties Dataset (NPD). Where there were no residential property values, these properties were left out of the analysis (which adds to the conservatism of the result). In many situations commercial properties are only given an annual rental value rather than a capital value. The capital value is usually calculated from the rental value by applying the relevant yield factor. A yield of 5.5 per cent has been suggested as acceptable for miscellaneous unvalued properties (Halcrow 2005). This has been applied to obtain estimates for capital value of properties that are only given a rental value by the NPD. This gives the best estimate of the value of commercial properties without going into detail that is not appropriate for SMP-level assessments. The benefits calculated by the value of defended properties are only realised once the defences have reached the end of their useful life under a scenario of no active intervention. Using the analysis completed as part of the defence assessment task, an average residual life was obtained for each section of defence. The residual life for the defences of each PDZ has been taken as the lowest average residual life of all the defence elements in that PDZ. In certain places residual life has not been assessed, either because defence is provided by natural features (dunes or a shingle ridge), or there are no records in the defence database (quaysides at Wells and Blakeney). In these situations it has been assumed that the year 2020 is an adequate estimate of when the defence function of these features will fail. The economic viability assessment does not take into account the benefit of defences for agricultural land, or the cost of losing agricultural land to managed realignment. As the policies keep defending most of the better quality agricultural land in the area, at least in the first two epochs, this adds to the conservatism of the results. In general, the result of the assessment is conservative because it only includes benefits from protecting properties and does not include other benefits (risk to people, infrastructure, business, environment etc). This assumption needs to be taken into account in assessing whether the preferred policies are viable (see section H2.3). For all calculations, it has been assumed that epoch 1 will begin on 1 January 2009. Epoch 1 is therefore from 2009 to 2025, epoch 2 is from 2026 to 2055 and epoch 3 is from 2056 to 2105. All values have been discounted


back to the present day values using current guidance and an optimism bias of 60 per cent has been applied to all costs to reflect uncertainty (as suggested by the SMP guidance, appendix C). For PDZs where the preferred policy is no active intervention, and this is also the current management policy, no assessment has been made as there are no flood and coastal risk management costs associated with these options.

H2.2 Assumptions

Several assumptions have been made about maintaining and replacing defences and exactly when new defences will be built where they are needed as part of managed realignment policies. The assumptions on cost of the defences were based on appendix C of the SMP guidance and are shown in tables H2.1 and H2.2. Table H2.1: Estimated defence costs

Defence type

Replacement cost (£/km)

Maintenance cost

(£/km/year)**

Full life reconstruction required (1 per x

years)* Linear

structure 2,700,000 10,000 100

Beach management 5,100,000 20,000 50

Groyne fields 600,000 10,000 30 Table H2.2: Estimated future defence costs

Replacement cost increase for climate

change (£1,000/km)**

Maintenance cost increase for climate

change (£1,000/km/yr)**Defence type Epoch

1 Epoch

2 Epoch

3 Epoch

1 Epoch

2 Epoch

3 Linear

structure 2,700 4,050 5,400 10 15 20

Beach management 5,100 7,650 10,200 20 30 40

Groyne fields 600 900 1,200 10 15 20 *May be more frequent where erosion is higher ** From NADNAC 2004 - takes into account making structure higher, deeper and more resilient to increased exposure

As there is no information available about the age of the defences, assumptions were made where necessary about when they would need replacing. Appendix C (section C2.3) of the SMP guidance states that for linear defences full scheme reconstruction is needed every 100 years and for


groynes every 30 years (table H2.1). So, for linear defences, it is assumed they are replaced in 2055 (the middle of the SMP period) as this gives the best estimate of the present value. Note that for those PDZs with a managed realignment policy for epoch 3 we have assumed that the existing defences are not replaced in 2055 as this would be only a few years before the realignment would take place. This means that the hold the line defence replacement is calculated with epoch 2’s low unit costs, while the new defence for the managed realignment option is calculated with the higher unit costs valid for epoch 3. In reality of course, construction costs will develop gradually. The inaccuracy introduced is considered acceptable as part of the broad-scale analysis, but it does emphasise the need for more accurate economic assessment of the conditional options beyond the SMP. For groynes it has been assumed that they are first replaced in 2024, 15 years into the SMP, and then every 30 years from then on for the same reason as with linear defences. For specific frontages, assumptions have been made about specific maintenance regimes and defences. These are outlined in the analysis of the individual PDZs. Several of the PDZs have uncertain or conditional policies for the later epochs. For those cases, the economic assessment has been carried out for both options.

H2.3 Viability and funding

For each PDZ with a calculated benefit cost ratio, the report draws a conclusion about the viability of the draft policy: viable, marginally viable or not viable. Generally speaking, the SMP uses the following bands:

• BCR higher than 2: clearly viable • BCR between 1 and 2: marginally viable • BCR under 1: not viable

All calculations were done through broad-scale analysis, which is typically conservative. It only takes into account the benefit of defences for properties, not for infrastructure, agricultural land or wider unquantifiable benefits related to tourism, habitat creation etc. Even if a policy is considered to be viable, this does not guarantee that it will be affordable and funded in the future.

H3 Analysis

This section outlines the results of the broad-scale economic assessment. The results are summarised in a set of tables at the back of this appendix. Table H1 gives a summary of the economic assessments carried out for each PDZ where there are defences. For the purposes of this broad-scale assessment, these policies are calculated to have no damage costs. Table


H3 shows the supporting information and table H5 details the calculation of the costs associated with maintaining and replacing defences. PDZ1A – Old Hunstanton dunes The policy for this frontage is to hold the line for epoch 1 with the intention to remove defences to allow the dune system to develop naturally in epochs 2 and 3, while maintaining flood defence to houses and infrastructure. It is uncertain whether and when there will be a need for defences. For the purpose of the analysis, however, it has been assumed that 1.3 kilometres of new defences would be needed at the end of epoch 2 to protect properties at Old Hunstanton and Holme-next-the-Sea from tidal flood risk as the defence function of the dunes reduces. The broad-scale economic review has given a benefit-cost ratio of 4.4 so it can be concluded that the policy is clearly economically viable. PDZ1B – Holme dunes The policy for this frontage is to maintain the flood defence function of the dunes through minimum intervention. It has been assumed that, where there are no defences now, there will be no need to maintain the dunes in the future. This is an uncertainty and intervention may be needed at some point. However, this cannot be calculated so it has been excluded from the economic viability test. The possible long-term realignment in PDZ1C (Thornham sea bank) is likely to support the dunes. Where there are ‘soft dragon tooth’ defences it has been assumed that they are equivalent to groynes for the purpose of calculating the cost of maintaining and replacing them. Also, to account for the benefits of the potential realignment and associated increase in tidal prism in PDZ1C reducing pressure on the dunes, the increase in maintenance and replacement costs due to climate change between epochs 2 and 3 has not been included. The broad-scale economic review has given a benefit-cost ratio of 20.0 so it can be concluded that the policy is clearly economically viable. PDZ1C – Thornham sea bank The policy for this frontage is to maintain flood defence to the communities of Thornham, Holme-next-the-Sea and Old Hunstanton, including all their houses, historic assets and infrastructure together with potentially increasing the tidal exchange in Thornham harbour channel by realigning Thornham sea bank. So in epochs 1 and 2 the defences will be maintained where they are now, but for epoch 3 there are two possible policy options: either to carry out managed realignment at Thornham sea bank (while continuing to protect Thornham, Holme-next-the-Sea and Old Hunstanton) or to continue to hold the line here.


If realignment takes place in epoch 3 the defences at the western edge of the frontage will be partly removed. New defences will be required to protect Thornham, Holme-next-the-Sea and Old Hunstanton. The broad-scale economic review has given a benefit-cost ratio of 3.5. If the current defence line is held through all three epochs the broad-scale assessment reveals an overall benefit-cost ratio of 4.2. The higher benefit-cost ratio for hold the line in this case can be explained by the relatively long length of new defences required to continue to protect properties. It has to be noted that the new defence line will be much less exposed and on higher ground than the existing line. This is not, however, included in the broad-scale assessment, which means that the calculated benefit-cost ratio for managed realignment is a conservative estimate. Given the overall conservatism of the broad-scale assessment, it can be concluded that that both policy options are clearly economically viable. PDZ1D - Thornham The policy for this frontage is no active intervention from epoch 1 onwards. As there are no costs incurred under this policy option an economic assessment is not needed. PDZ2A – Thornham to Titchwell There are currently no defences along this frontage and there is no intention to build new defences in the future. The policy for this frontage is therefore to continue no active intervention for all epochs so an economic assessment is not needed. PDZ2B – Titchwell RSPB reserve The policy for this frontage is to hold the line at the realigned position for all three epochs. So the costs associated with this option are those needed to maintain the new defence line. The decision for this policy has already been made by the RSPB, which is expected to bear the cost of maintaining the defences. It is therefore less important for the SMP to ascertain economic viability for this frontage. The broad-scale economic review has revealed that the only property at risk of tidal flooding along this frontage is the Titchwell RSPB reserve visitor centre. The national property database does not give a value for this property so the analysis assumes there are no economic benefits for the preferred policy. However, there are other benefits that this broad-scale review does not consider such as the tourism value of the reserve and the actual benefit value of this land. Based on the RSPB’s recent decision to realign and keep maintaining the defences for 50 years, the preferred policy can be assumed to be economically viable.


PDZ2C – Titchwell village There are currently no defences along this frontage and there is no intention to build new defences in the future. The policy for this frontage is therefore to continue no active intervention for all epochs so an economic assessment is not needed. PDZ2D – Reclaimed grazing marsh at Brancaster The policy for this frontage is to hold the line in epoch 1. For epochs 2 and 3, the policy is either hold the line or managed realignment, depending on the results of monitoring and assessments. If and when realignment takes place, new defences will be needed to protect properties in Brancaster from flooding from the west through this PDZ. There is currently an embankment that runs north to south protecting properties on Broad Lane that would be maintained and extended to account for sea level rise. The broad-scale economic review has given a benefit-cost ratio of 3.9 if realignment takes place at the start of epoch 2. This is clearly economically viable. The alternative policy of hold the line through all three epochs has a benefit-cost ratio of 0.7 which suggests it is not viable (based on the broad-scale analysis carried out for this SMP). PDZ2E – Royal West Norfolk golf club The policy for this frontage is to hold the line for all epochs. The actual scale of future defence maintenance and potential extension is uncertain. It has been assumed that the geotextile bags fronting the dunes east of the clubhouse are equivalent to groynes for the purpose of maintenance and replacement costs and that the current length and type of defences remains sufficient. As for the Titchwell RSPB reserve, the cost of the defences is borne by a private defence owner (the Royal West Norfolk golf club) so it is less important for the SMP to ascertain economic viability for this frontage. The broad-scale economic review has given a benefit-cost ratio of 0.3 so it would be concluded that the preferred policy is not economically viable. However, this is again a conservative assessment based on NPD property value only, which ignores the wider value of the protected features. A more detailed assessment to confirm economic viability for this frontage is not needed, as the actual intent of management is to allow the golf club to hold the line, which they intend to do. PDZ2F – Brancaster and Brancaster Staithe The policy for this frontage is to allow the private defence owners to hold the line for all epochs. This will mean maintaining the existing defences to continue protecting properties in Brancaster and Brancaster Staithe.


The broad-scale economic review has given a benefit-cost ratio of 1.2 so it can be concluded that the policy is marginally economically viable (given the conservatism of the assessment). PDZ2G – Reclaimed areas behind Scolt Head Island The policy for this frontage is to maintain flood defence to all communities and their houses and infrastructure, together with potentially increasing tidal exchange by realigning the reclaimed Deepdale, Norton and Overy marshes in the long term, if supported by monitoring and research during epochs 1 and 2. So, in epochs 1 and 2, the defences will be maintained where they are now, but for epoch 3 there are two possible policy options: either to carry out managed realignment at Deepdale, Norton and Overy marshes (while continuing to hold the line for the River Burn valley) or to continue to hold the line for all areas. If realignment takes place in epoch 3, defences will be partly removed at Deepdale and Norton marshes and at Overy marshes. New defences will be needed to protect Burnham Deepdale, Burnham Norton, the A149, the River Burn valley and the eastern edge of Burnham Overy Staithe. A new defence line will also be needed between Marsh House Farm and Holkham dunes to protect features in the tidal flood zone that extends eastwards to Wells-next-the-Sea. The broad-scale economic review has given an overall benefit-cost ratio of 1.3, which is marginally viable. However, this varies considerably between the individual flood compartments. For Deepdale and Norton marsh alone the benefit-cost ratio is 0.3, for the River Burn valley it is 5.7 and for Overy marshes it is 2.1. If the current defence line is held through all three epochs the broad-scale assessment reveals an overall benefit-cost ratio of 0.8, with individual benefit-cost ratios of 0.2 for Deepdale and Norton marshes, 5.7 for the River Burn valley and 2.1 for Overy marshes. This would not be viable, although more detailed assessment is needed to confirm the accuracy of the broad-scale assessment. PDZ2H – Burnham Overy Staithe The policy for this frontage is to hold the line for all three epochs. This will mean maintaining the existing defences that currently protect properties in Burnham Overy Staithe. The broad-scale economic review has given a benefit-cost ratio of 0.7, which suggests it is not viable (based on the broad-scale analysis carried out for this SMP). PDZ2I – Holkham dunes The policy for this frontage is to maintain the flood defence function of the dunes through minimum intervention. Where there are currently defences at the eastern end of the frontage, it has been assumed that these will be maintained and replaced as with any other defence. The remainder of the


frontage has no defences at present and the actual level of maintenance that will be needed is uncertain. The following maintenance schedule has been assumed to maintain the flood defence function of the dunes. In epoch 1 no maintenance will be needed. In epoch 2 the minimum maintenance level of one kilometre of defence will be needed (linear or groynes) and this will continue into epoch 3. The broad-scale economic review has given a benefit-cost ratio of 4.8 so it can be concluded that the policy is clearly economically viable. PDZ2J – Wells flood embankment The policy for this frontage is to hold the line for all three epochs. This will mean maintaining the 1.08 kilometre-long embankment that currently protects numerous features in the tidal flood zone that extends westwards to Burnham Overy Staithe. The broad-scale economic review has given a benefit-cost ratio of 2.4. Given the conservatism of the assessment, it can be concluded that the policy is clearly economically viable. PDZ2K – Wells quay The policy for this frontage is to hold the line for all three epochs. This will mean maintaining the 0.78 kilometres of defences that currently protect properties in Wells-next-the-Sea. The broad-scale economic review has given a benefit-cost ratio of 3.3 so it can be concluded that the policy is clearly economically viable. PDZ2L – Wells east bank The policy for this frontage is to hold the line for all three epochs. This will mean maintaining the existing defences to continue protecting properties in Wells-next-the-Sea and the A149. The broad-scale economic review has given a benefit-cost ratio of 5.2, so it can be concluded that the policy is clearly economically viable. PDZ2M – Stiffkey bay There are currently no defences along this frontage and there is no intention to build new defences in the future. The policy for this frontage is therefore to continue no active intervention for all epochs so an economic assessment is not needed. PDZ3A – Reclaimed areas behind Blakeney Spit The policy for this frontage is to maintain flood defence to all houses and infrastructure, together with gradually increasing tidal exchange by realigning the reclaimed areas at Blakeney Freshes in the medium term and, if confirmed during epochs 1 and 2, at Cley marshes in the long term. In epoch 1 the defences will be maintained where they are now. This means there are


two options in epoch 3: either to continue holding the line at Cley west bank or to realign. In epoch 2, defences at Blakeney Freshes marshes will be partly removed close to Blakeney to improve navigation to the harbour and moorings. This will mean building new defences to protect some properties in Blakeney. If the epoch 3 realignment at Cley marshes is confirmed, defences on the western margin of Cley marshes will be partly removed. This will need a new defence line to protect the A149 and the flood zone behind the Cley to Salthouse shingle ridge to the east. The broad-scale economic review has given an overall benefit-cost ratio of 1.9 So it can be concluded that, as a whole, a preferred policy that includes realignment is at least marginally economically viable. However, there is a significant difference between the intended sites of realignment and the two river valleys when they are considered separately. The Stiffkey and Glaven (including Cley) valleys and Morston (which remains defended) have individual benefit-cost ratios of 3.1, 10.0 and 0.8 respectively. However, the realignments at Blakeney Freshes and Cley marshes have individual benefit-cost ratios of 0.6 and 0.4 respectively. For the Cley realignment there are considerable non property-related benefits (such as the A149), so this is likely to be economically viable on its own. For Blakeney Freshes, the economic benefits for navigation, which are an important driver, are not included in the assessment. If the epoch 3 realignment at Cley marshes does not take place, the broad-scale economic review reveals identical benefit cost ratios for all PDZs apart from Cley marshes. This would have a benefit cost ratio of 0.6, which is slightly better than the realignment option, but still suggests it is not viable. The overall benefit cost ratio would be 2.2 which is clearly economically viable. PDZ3C - Blakeney The policy for this frontage is to hold the line for all three epochs. This will mean maintaining the whole length of defences that currently protect properties in Blakeney. The broad-scale economic review has given a benefit-cost ratio of 2.0 so it can be concluded that the policy is clearly economically viable. PDZ3D – Cley to Salthouse The policy for this frontage is to maintain the flood defence function of the shingle ridge through minimum intervention. To achieve this, the following maintenance schedule has been assumed. In epoch 1 there will be no need for maintenance as current processes suggest that the flood defence function will not be under threat. In epoch 2, minimum annual maintenance will be needed once every 10 years and there will be no increase in this cost in epoch 3 due to climate change.


The broad-scale economic review has given a benefit-cost ratio of 9.6 so it can be concluded that the policy is clearly economically viable. Analysis of super-frontages The main SMP document reports about the economic viability at the level of the super-frontages only. For super-frontage 1, the total economic benefits of the policy are estimated to exceed the costs, although not by a wide margin: the plan is marginally viable. The overall benefit-cost ratio is 1.9 if there is no realignment at Thornham sea bank and 1.8 if managed realignment takes place. As explained in the analysis of PDZ1C, the calculated benefit-cost ratio for the managed realignment option is particularly conservative. For super-frontage 2, the total economic benefits of the policy are estimated to be in the same order as the costs if the existing defence lines are held throughout. If the defences are realigned, the benefits are estimated to exceed the costs, although only by a very small margin. The overall benefit-cost ratio is 1.2 with realignments and 0.9 without the realignments. Holding the line has a lower benefit-cost ratio because it would involve continued maintenance (including rebuilding) of long lengths of defences, while the timing of the realignments (largely in epoch 3) coincides with the assumed timescale for rebuilding the existing defences. For super-frontage 3, the total economic benefits of the policy are estimated to exceed the costs, although not by a wide margin: the plan is marginally viable. This is the case for both policy options at Cley west bank (hold the line or managed realignment in epoch 3). The overall benefit-cost ratio is 1.9 if the realignment at Cley bank takes place, while it is 2.1 if the line is held there. This is because of the assumption that Cley east bank would be upgraded to act as a flood defence, in addition to new defences for Cley. Further supporting information for the analysis at super-frontage level is in tables H2, H4 and H6.

H4 References

Halcrow 2005. National Property Dataset Update 2005. Halcrow Group Limited. Swindon.


Table H 1 Economic assessment summary for each policy development zone

Assumed defence works and costs Calculation of damages and benefits Broad-scale economic review

Location Previous studies

Broad-scale review (this SMP)

Epoch 1 (2009 to

2025)

Epoch 2 (2026 to

2055)

Epoch 3 (2056 to

2105)

Comments

Continue maintaining

existing gabion

defences and groyne field to

maintain protection. Cost: £0.9

million.

Defences to dune system removed and new defences

needed to protect

properties in Old

Hunstanton and Holme

from flood risk Cost: £9.4

million.


defences built in epoch 2 to

protect properties in

Old Hunstanton and Holme from flood

risk. Cost: £2.3

million.

PDZ1A Old

Hunstanton dunes

No data currently available

NAI damages: by 2025: up to £19.0 million by 2055: up to £24.0 million by 2105: up to £36.2 million Maintain flood defence function of dunes through minimum intervention damages: by 2025: none by 2055: none by 2105: none

The plan for this policy development zone is clearly economically viable. The PV

benefits amount to £15.6 million by 2105 whereas the PV costs amount to £3.5 million.

This PP has a BCR of 4.4

reflecting the fact that the

properties in Old Hunstanton and Holme-next-the-

Sea remain protected.





Epoch 1 (2009 to

2025)

Epoch 2 (2026 to

2055)

Epoch 3 (2056 to

2105)

Comments

The soft defences

currently in place in the

dunes will be maintained to

provide protection. Cost: £0.5

million.

The soft defences




million.

The soft defences




million. PDZ1B Holme

dunes



The plan for this policy development zone is clearly economically viable. The PV benefits amount to £15.6 million by 2105 whereas the

PV costs amount to £0.8 million.

This PP has a BCR of 20.0 reflecting the

fact that properties in Old Hunstanton and Holme-next-the-






Epoch 1 (2009 to

2025)

Epoch 2 (2026 to

2055)

Epoch 3 (2056 to

2105)

Comments


existing defences to


million.




million.

Thornham sea bank no

longer maintained.

New defences needed to

protect properties. Cost: £17

million.

PDZ1C (with realignment)

Thornham sea bank


NAI damages: by 2025: up to £19.0 million by 2055: up to £24.0 million by 2105: up to £36.2 million Maximise tidal exchange damages: by 2025: none by 2055: none by 2105: none




reflecting the fact that



PDZ1C (without realignment)

Thornham sea bank


NAI damages: by 2025: up to £19.0 million by 2055: up to £24.0 million by 2105: up to £36.2 million




million.




million.




million.


reflecting the fact that







Epoch 1 (2009 to

2025)

Epoch 2 (2026 to

2055)

Epoch 3 (2056 to

2105)

Comments

Hold the line damages: by 2025: none by 2055: none by 2105: none



PDZ1D Thornham NAI – No assessment

PDZ2A Thornham to Titchwell NAI – No assessment





Epoch 1 (2009 to

2025)

Epoch 2 (2026 to

2055)

Epoch 3 (2056 to

2105)

Comments


existing defences and

build new defences in

current realignment to

maintain protection Cost: £0.5

million.



build new defences in realigned position to maintain

protection. Defences

assumed to be replaced in

this epoch. Cost: £14.1

million.



build new defences in realigned position to maintain

protection Cost: £3.4

million.

PDZ2B Titchwell

RSPB reserve


NAI damages: by 2025: unknown by 2055: unknown by 2105: unknown Hold the line at the realigned position damages: by 2025: none by 2055: none by 2105: none

The PV benefits amount to £0 as there is no value for the RSPB reserve. The PV costs

amount to £4.7 million.

The decision to implement the realignment at

the RSPB reserve has already been made so the

SMP does not need to

calculate economic

viability for this frontage.

PDZ2C Titchwell village NAI – No assessment





Epoch 1 (2009 to

2025)

Epoch 2 (2026 to

2055)

Epoch 3 (2056 to

2105)

Comments



provide protection Cost: £0.5

million.

Defences partially

removed and maintenance stops so no

costs.

Defences partially

removed and maintenance stops so no

costs.

PDZ2D (with realignment)

Reclaimed grazing

marsh at Brancaster

Brancaster West Marsh

engineers report

NAI damages: by 2025: up to £3.9 million by 2055: up to £4.6 million by 2105: up to £6.2 million Create new intertidal habitat damages: by 2025: none by 2055: none by 2105: none

This option is clearly economically viable. The PV benefits amount to £2.9 million by

2105 whereas the PV costs amount to £0.4 million.

The broad-scale economic review gives a BCR of 3.9 for this PP. The Brancaster

West Marsh engineers report

suggested a BCR of 0.8 for

full realignment. This looked at a

shorter timescale so no properties in the tidal flood zone

were considered.





Epoch 1 (2009 to

2025)

Epoch 2 (2026 to

2055)

Epoch 3 (2056 to

2105)

Comments




million.



provide protection

Cost: £12.9 million.




million. PDZ2D (without realignment)

Reclaimed grazing

marsh at Brancaster

Brancaster West Marsh

engineers report

NAI damages: by 2025: up to £3.9 million by 2055: up to £4.6 million by 2105: up to £6.2 million Hold the line damages: by 2025: none by 2055: none by 2105: none

This option is likely to be not economically viable. The PV benefits amount to £2.9 million by 2105 whereas the PV costs amount to £4.3

million.

The broad-scale economic review gives a BCR of 0.7 for this PP. The Brancaster

West Marsh engineers report

suggested a BCR of 0.8 for

full realignment. This looked at a

shorter timescale so no properties in the tidal flood zone

were considered.

dix H – Economic appraisal Final plan October 2010

- Appen




Epoch 1 (2009 to

2025)

Epoch 2 (2026 to

2055)

Comments Epoch 3 (2056 to

2105)




million.



provide protection.

Linear defences

replaced in this epoch. Cost: £8.2

million.




million.

PDZ2E Royal West Norfolk golf

club



The PV benefits amount to £0.8 million by 2105 whereas the PV costs amount to £3.0

million.

North Norfolk SMP2 - H 19

This PP has a BCR of 0.3 from the broad-scale

assessment.

PDZ2F

Brancaster to

Brancaster Staithe






million.



provide protection.

Linear defences

replaced in




million.

This PP has a BCR of 1.2 as properties in

Brancaster and Brancaster

Staithe remain protected by

private defence owners.





Epoch 1 (2009 to

2025)

Epoch 2 (2026 to

2055)

Epoch 3 (2056 to

2105)

Comments


million. Hold the line damages: by 2025: none by 2055: none by 2105: none

The plan for this policy development zone is marginally economically viable. The PV benefits amount to £10.4 million by 2105

whereas the PV costs amount to £8.5 million.

PDZ2G (with realignment)

Reclaimed areas behind Scolt Head

Island


NAI damages: by 2025: up to £15.2 million by 2055: up to £27.6 million by 2105: up to £33.9 million Gradual increase in tidal exchange to support navigation damages: by 2025: none by 2055: none by 2105: none




million.




million.

Existing defences no

longer maintained at Overy marsh and Deepdale

and Norton marshes.

New defences built

to protect properties, A149 and

flood zone at Wells.


This PP has an overall BCR of 1.3. However

this varies considerably between the

three compartments. The River Burn valley alone has

a BCR of 5.7, while Deepdale

and Norton marshes and

Overy marshes only have BCRs of 0.3 and 2.1





Epoch 1 (2009 to

2025)

Epoch 2 (2026 to

2055)

Epoch 3 (2056 to

2105)

Comments


provide protection for River Burn outfall and

new defences at Deepdale and Norton marshes.


respectively.

This option is marginally economically viable. The PV benefits amount to £15.2

million by 2105 whereas the PV costs amount to £11.6 million.

PDZ2G (without realignment)

Reclaimed areas behind Scolt Head

Island






million.




million.




million.

This PP has an overall BCR of 0.8. However

this varies considerably between the

three compartments.





Epoch 1 (2009 to

2025)

Epoch 2 (2026 to

2055)

Epoch 3 (2056 to

2105)

Comments

Hold the line damages: by 2025: none by 2055: none by 2105: none This option is likely to be not viable. The PV

benefits amount to £15.2 million by 2105 whereas the PV costs amount to £18.1 million.

The River Burn valley alone has

a BCR of 5.7, while Deepdale

and Norton marshes and

Overy marshes only have BCRs of 0.2 and 2.1 respectively.

PDZ2H Burnham

Overy Staithe






million.



provide protection.

Linear defences

replaced in this epoch. Cost: £8.6

million.




million.

This PP has a BCR of 0.7.





Epoch 1 (2009 to

2025)

Epoch 2 (2026 to

2055)

Epoch 3 (2056 to

2105)

Comments

The plan for this policy development zone is likely to be not viable. The PV benefits

amount to £2.0 million by 2105 whereas the PV costs amount to £2.9 million.

PDZ2I Holkham dunes



Continue maintaining existing hard defences at eastern end

of the frontage to maintain

protection. Groynes

replaced this epoch.


Continue maintaining existing hard defences at eastern end


protection. Groynes and

linear defences

replaced this epoch. Some

maintenance of dunes needed.



existing hard defences at eastern end


protection. Groynes

replaced this epoch. Some

maintenance of dunes needed.


This PP has a BCR of 4.8. The main costs are

incurred through maintaining the defences at the eastern end of the frontage.





Epoch 1 (2009 to

2025)

Epoch 2 (2026 to

2055)

Epoch 3 (2056 to

2105)

Comments






million.



provide protection. Defences



million.




million.

PDZ2J Wells flood embankment










Epoch 1 (2009 to

2025)

Epoch 2 (2026 to

2055)

Epoch 3 (2056 to

2105)

Comments




million.






million.




million.

PDZ2K Wells quay No data currently available


The plan for this policy development zone is clearly economically viable. The PV benefits



PDZ2L Wells east bank


NAI damages: by 2025: up to £0 by 2055: up to £28.1 million by 2105: up to £31.1 million




million.




million.




million.






Epoch 1 (2009 to

2025)

Epoch 2 (2026 to

2055)

Epoch 3 (2056 to

2105)

Comments

Hold the line damages: by 2025: none by 2055: none by 2105: none



PDZ2M Stiffkey bay NAI – No assessment

PDZ3A (with realignment at Cley)

Reclaimed areas behind

Blakeney Spit

Blakeney Freshes project

appraisal report

NAI damages: by 2025: up to £31.1 million by 2055: up to £38.6 million by 2105: up to £47.8 million Gradual increase in intertidal habitat damages: by 2025: none by 2055: none by 2105: none




million.

Defences no longer

maintained at Blakeney

Freshes. New defences built

to protect properties. Continue to

maintain existing

defences to sustain

protection for rest of PDZ. Cost: £19.8

million.

Defences no longer

maintained at Cley

marshes. New

defences built to protect properties. Continue

maintaining existing

defences to sustain


million.

This PP has an overall BCR of 1.9. However, the ratios for

individual compartments

vary a lot. Blakeney

Freshes (BCR 0.6), Cley

marshes (BCR 0.4) and

Morston (BCR 0.8) are not

economically viable when considered

alone.





Epoch 1 (2009 to

2025)

Epoch 2 (2026 to

2055)

Epoch 3 (2056 to

2105)

Comments

This option is at least marginally viable. The PV benefits amount to £25.7 million by 2105





million.

Defences no longer

maintained at Blakeney

Freshes. New defences built

to protect properties. Continue

maintaining existing

defences to sustain


million.



sustain protection for rest of PDZ. Cost: £7.3

million.

PDZ3A (without realignment at Cley marshes)

Reclaimed areas behind

Blakeney Spit

Blakeney Freshes project

appraisal report

NAI damages: by 2025: up to £31.1 million by 2055: up to £38.6 million by 2105: up to £47.8 million Hold the line damages: by 2025: none by 2055: none by 2105: none This option is clearly economically viable.

The PV benefits amount to £25.7 million by 2105 whereas the PV costs amount to £13.8

million.

This PP has an overall BCR of 2.2. However,

the ratios for the individual

compartments vary a lot. Blakeney

Freshes (BCR 0.6), Cley

marshes (BCR 0.6) and

Morston (BCR 0.8) are not

economically viable when considered

alone.





Epoch 1 (2009 to

2025)

Epoch 2 (2026 to

2055)

Epoch 3 (2056 to

2105)

Comments

PDZ3B Stiffkey to Morston NAI – No assessment




million.






million.




million.

PDZ3C Blakeney No data currently available




This PP has a BCR of 2.0.





Epoch 1 (2009 to

2025)

Epoch 2 (2026 to

2055)

Epoch 3 (2056 to

2105)

Comments

No maintenance

needed to maintain flood

defence function of the shingle ridge.

Limited maintenance




Limited maintenance



Cost: £0.6 million. PDZ3D Cley to

Salthouse


NAI damages: by 2025: up to £3.6 million by 2055: up to £3.6 million by 2105: up to £5.5 million Maintain flood defence function of shingle ridge through minimum intervention damages: by 2025: none by 2055: none by 2105: none



This PP has a BCR of 9.6 with

the assumed maintenance

schedule


Table H2 Economic assessment summary for each super-frontage




Epoch 1 (2009 to

2025)

Epoch 2 (2026 to

2055)

Epoch 3 (2056 to

2105)

Comments

Cost: £1.8 million

Cost: £11.5 million


SF1 (with realignment)

Old Hunstanton

to Thornham


NAI damages: By 2025: up to £19.0 million By 2055: up to £24.0 million By 2105: up to £36.2 million MR policies damages: By 2025: none By 2055: none By 2105: none



This suite of policies has a BCR of 1.8.

Cost: £1.8 million


Cost: £6.3 million

SF1 (without realignment)

Old Hunstanton

to Thornham


NAI damages: By 2025: up to £19.0 million By 2055: up to £24.0 million By 2105: up to £36.2 million








Epoch 1 (2009 to

2025)

Epoch 2 (2026 to

2055)

Epoch 3 (2056 to

2105)

Comments

Hold the line damages: By 2025: none By 2055: none By 2105: none

Cost: £5.8 million



SF2 (with realignments)

Thornham to Stiffkey marshes



The plan for this policy development zone is marginally economically viable. The PV benefits amount to £48.6 million by 2105 whereas the PV costs amount to £44.6

million.


Cost: £5.7 million


Cost: £40.2 million SF2

(without realignments)

Thornham to Stiffkey marshes


NAI damages: By 2025: up to £78.2 million By 2055: up to £ 88.3million By 2105: up to

The plan for this policy development zone is not likely to be economically viable. The

PV benefits amount to £48.6 million by 2105 whereas the PV costs amount to £51.8






Epoch 1 (2009 to

2025)

Epoch 2 (2026 to

2055)

Epoch 3 (2056 to

2105)

Comments

£108.8 million Hold the line damages: By 2025: none By 2055: none By 2105: none

million.

Cost: £2.6 million



SF3 (with realignments)

Stiffkey marshes to Salthouse



The plan for this policy development zone is marginally economically viable. The PV benefits amount to £32.6 million by 2105 whereas the PV costs amount to £17.1

million.


Cost: £2.6 million


Cost: £10.3 million SF3

(without realignments)

Stiffkey marshes to Salthouse


NAI damages: By 2025: up to £40.9 million By 2055: up to

The plan for this policy development zone is clearly economically viable The PV






Epoch 1 (2009 to

2025)

Epoch 2 (2026 to

2055)

Epoch 3 (2056 to

2105)

Comments

£49.8 million By 2105: up to £60.4 million Hold the line damages: By 2025: none By 2055: none By 2105: none

benefits amount to £32.6 million by 2105 whereas the PV costs amount to £15.3

million.


Table H3 Supporting economic data – summary table for each policy development zone Asset value loss for each

epoch (damages) (£) Cumulative property damage/loss (PV) (£) Final plan

Policy unit Epoch NAI Final plan NAI Final

plan

Management cost for each epoch (final

plan) 1

Property damages averted

(PV)

Costs (PV)2 (£)

1 18,976,915 - 11,947,586 - 853,155 11,947,586 657,136 2 4,994,063 - 13,857,472 - 9,396,000 1,909,886 2,530,398 PDZ1A 3 12,224,389 - 15,638,096 - 2,255,040 1,780,624 328,473 1 18,976,915 - 11,947,586 - 518,563 11,947,586 329,357 2 4,994,063 - 13,857,472 - 909,360 1,909,886 276,236 PDZ1B 3 12,224,389 - 15,638,096 - 1,151,856 1,780,624 174,613 1 18,976,915 - 12,838,953 - 450,976 12,838,953 347,361 2 4,994,063 - 14,748,839 - 1,193,760 1,909,886 3,055,818

PDZ1C (with

realignment) 3 12,224,389 - 16,529,463 - 17,003,520 1,780,624 2,848,998 1 18,976,915 - 12,838,953 - 450,976 12,838,953 347,361 2 4,994,063 - 14,748,839 - 11,937,600 1,909,886 3,214,867

PDZ1C (without

realignment) 3 12,224,389 - 16,529,463 - 2,865,024 1,780,624 417,325 1 0 - 0 - 533,120 0 410,632 2 0 - 0 - 14,112,000 0 3,800,446 PDZ2B 3 0 - 0 - 3,386,880 0 493,338

1 Including 60 per cent optimism bias 2 Including 60 per cent optimism bias


Asset value loss for each epoch (damages) (£)

Cumulative property damage/loss (PV) (£) Final plan


plan


plan) 1


(PV)

Costs (PV)2 (£)

1 3,856,669 - 2,428,102 - 486,336 2,428,102 374,597 2 783,643 - 2,727,792 - 658,800 299,690 348,211

PDZ2D (with

realignment) 3 1,521,463 - 2,949,411 - 259,200 221,619 37,755 1 3,856,669 - 2,428,102 - 486,336 2,428,102 374,597 2 783,643 - 2,727,792 - 12,873,600 299,690 3,466,937

PDZ2D (without

realignment) 3 1,521,463 - 2,949,411 - 3,089,664 221,619 450,044 1 1,319,701 - 830,864 - 538,800 830,864 377,848 2 0 - 830,864 - 8,172,000 0 2,213,439 PDZ2E 3 0 - 830,864 - 2,587,200 0 379,714 1 11,974,218 - 8,883,220 - 960,704 8,883,220 739,975 2 1,743,055 - 9,549,819 - 25,430,400 666,599 6,848,559 PDZ2F 3 6,374,296 - 10,478,309 - 6,103,296 928,490 889,016 1 15,243,639 - 9,597,170 - 2,048,786 9,597,170 1,578,061 2 12,306,770 - 14,239,235 - 6,772,608 4,642,065 2,419,664

PDZ2G (with

realignment) 3 6,334,658 - 15,161,952 - 32,688,922 922,717 7,552,378 1 15,243,639 - 9,597,170 - 2,048,786 9,597,170 1,578,061 2 12,306,770 - 14,239,235 - 54,228,240 4,642,065 14,604,071

PDZ2G (without

realignment) 3 6,334,658 - 15,161,952 - 13,014,605 922,717 1,895,728 1 2,728,831 - 1,718,032 - 324,224 1,718,032 249,731 2 0 - 1,718,032 - 8,582,400 0 2,311,292 PDZ2H 3 1,653,590 - 1,958,897 -

2,059,776240,865 300,030





plan


plan) 1


(PV)

Costs (PV)2 (£)

1 15,243,639 - 9,597,170 - 0 9,597,170 570,866 2 1,616,096 - 10,215,216 - 3,050,856 618,046 955,122 PDZ2I 3 731,323 - 10,321,742 - 4,043,462 106,526 604,102 1 15,243,639 - 9,597,170 - 486,064 9,597,170 374,387 2 1,616,096 - 10,215,216 - 12,866,400 618,046 3,464,999 PDZ2J 3 731,323 - 10,321,742 - 3,087,936 106,526 449,794





plan


plan) 1


(PV)

Costs (PV)2 (£)

1 8,262,790 5,202,131 - 212,160 5,202,131 163,415 2 1,991,100 5,963,590 - 5,616,000 761,459 1,512,422 PDZ2K 3 1,580,828 6,193,856 - 1,347,840 230,266 196,329 1 0 - 0 - 197,120 0 184,365 2 28,072,476 - 10,566,608 - 6,336,000 10,566,608 1,706,323 PDZ2L 3 3,009,145 - 11,004,925 - 1,520,640 438,317 221,499 1 31,122,676 - 21,544,907 - 2,181,389 21,544,907 1,723,270 2 7,526,192 - 24,360,840 - 19,786,608 2,815,933 5,841,119

PDZ3A (with

realignment at Cley

marshes)

3 9,188,050 - 25,699,186 - 28,267,488 1,338,346

6,198,548 1 31,122,676 - 21,544,907 - 2,181,389 21,544,907 1,723,270 2 7,526,192 - 24,360,840 - 31,495,968 2,815,933 8,847,340

PDZ3A (without

realignment at Cley

marshes)

3 9,188,050 - 25,699,186 - 7,284,384 1,338,346 1,061,055

1 9,780,215 - 6,157,479 - 384,880 6,157,479 296,451 2 1,456,548 - 6,714,508 - 10,188,000 557,029 2,743,689 PDZ3C 3 1,316,834 - 6,906,320 - 2,445,120 191,812 356,160 1 3,611,049 - 2,273,463 - 0 2,273,463 0 2 0 - 2,273,463 - 358,632 0 153,877 PDZ3D 3 1,932,760 - 2,554,992 - 597,720 281,529 111,170


Table H4 Supporting economic data – summary table for each super-frontage Asset value loss for each

epoch (damages) (£) Cumulative property damage/loss (PV) (£) Final plan

Policy unit Epoch NAI Final plan NAI Final plan


plan) 3


(PV)

Costs (PV)4 (£)

1 18,976,915 12,838,953 1,822,694 12,838,953 1,333,854 2 4,994,063 14,748,839 22,242,960 1,909,886 6,021,501 SF1 3 12,224,389 16,529,463 6,271,920 1,780,624 920,411 1 43,385,848 0 28,659,519 0 5,787,314 28,659,519 5,023,877 2 44,897,044 0 45,595,940 0 91,597,464 16,936,421 25,580,477 SF2 3 20,473,980 0 48,578,214 0 57,085,152 2,982,274 11,123,956 1 40,902,891 0 27,702,386 0 2,566,269 27,702,386 2,019,720 2 8,982,740 0 31,075,348 0 30,333,240 3,372,962 8,738,685 SF3 3 10,504,884 0 32,605,506 0 31,310,328 1,530,158 6,665,878

3 Including 60 per cent optimism bias 4 Including 60 per cent optimism bias


Table H5 Supporting economic data – defence cost calculations for each policy development zone

Replacement Maintenance Total cost (£) PV costs (£)

Length (km) Length (km)

Policy unit Epoch B L G Cost (£)5 B L G Cost (£)5 Total cost

With optimism bias (60%)

Cumulative total PV total


Cumulative PV total

1 0 0 0 0 0 1.85 1.29 533,222 533,222 853,155 853,155 410,710 657,136 657,136

2 0 1.31 0 5,825,250 0 1.31 0 587,250 5,872,500 9,396,000 10,249,155 1,581,499 2,530,398 3,187,534 PDZ1A

3 0 0 0 0 0 1.31 0 1,409,400 1,409,400 2,255,040 12,504,195 205,296 328,473 3,516,007

1 0 0 0.42 252,600 0 0 0.42 71,502 324,102 518,563 518,563 205,848 329,357 329,357

2 0 0 0.42 378,900 0 0 0.42 189,450 568,350 909,360 1,427,923 172,647 276,236 605,593 PDZ1B

3 0 0 0.42 378,900 0 0 0.42 341,010 719,910 1,151,856 2,579,779 109,133 174,613 780,207

1 0 0 0 0 0 1.658 0 281,860 281,860 450,976 450,976 217,100 347,361 347,361

2 0 0 0 0 0 1.658 0 746,100 746,100 1,193,760 1,644,736 285,332 456,531 803,892 PDZ1C (with managed realignment) 3 0 1.64 0 8,856,000 0 1.640 0 1,771,200 10,627,200 17,003,520 18,648,256 2,465,432 3,944,691 4,748,583

1 0 0 0 0 0 1.658 0 16,580 281,860 450,976 450,976 217,100 347,361 347,361

2 0 1.66 0 6,714,900 0 1.658 0 24,870 746,100 11,937,600 12,388,576 2,009,292 3,214,867 3,562,228

PDZ1C (without managed realignment) 3 0 0 0 0 0 1.658 0 33,160 1,790,640 2,865,024 15,253,600 260,828 417,325 3,979,553

1 0 0 0 0 0 1.96 0 333,200 333,200 533,120 533,120 256,645 410,632 410,632

2 0 1.96 0 7,938,000 0 1.96 0 882,000 8,820,000 14,112,000 14,645,120 2,375,279 3,800,446 4,211,078

PDZ2B 3 0 0 0 0 0 1.96 0 2,116,800 2,116,800 3,386,880 18,032,000 308,337 493,338 4,704,416








Cumulative PV total

Replacement Maintenance Total cost (£) PV Costs (£)






Cumulative PV total

1 0 0 0 0 0 1.79 0 303,960 303,960 486,336 486,336 234,123 374,597 374,597

2 0 0.09 0 344,250 0 0.15 0 67,500 411,750 658,800 1,145,136 217,632 348,211 722,808 PDZ2D (with realignment)

3 0 0 0 0 0 0.15 0 162,000 162,000 259,200 1,404,336 23,597 37,755 760,563

1 0 0 0 0.00 0 1.79 0 303,960 303,960 486,336 486,336 234,123 374,597 374,597

2 0 1.79 0 7,241,400 0 1.79 0 804,600 804,600 12,873,600 13,359,936 2,166,836 34,66,938 2,400,959 PDZ2D (without realignment) 3 0 0 0 0.00 0 1.79 0 1,931,040 1,931,040 3,089,664 16,449,600 281,278 450,045 2,682,237

1 0 0 0.2 120,000 0 1.08 0.2 216,750 336,750 538,800 538,800 236,155 377,848 377,848

2 0 1.08 0.2 4,533,750 0 1.08 0.2 573,750 5,107,500 8,172,000 8,710,800 1,383,399 2,213,439 2,591,287 PDZ2E

3 0 0 0.2 240,000 0 1.08 0.2 1,377,000 1,617,000 2,587,200 11,298,000 237,321 379,714 2,971,000

1 0 0 0 0 0 3.53 0 600,440 600,440 960,704 960,704 462,484 739,975 739,975

2 0 3.53 0 14,304,600 0 3.53 0 1,589,400 15,894,000 25,430,400 26,391,104 4,280,350 6,848,559 7,588,534 PDZ2F

3 0 0 0 0 0 3.53 0 3,814,560 3,814,560 6,103,296 32,494,400 555,635 889,016 8,477,550








Cumulative PV total

1 0 0 0 0 0 5.29 0 52,907 899,419 899,419 1,439,070 1,439,070 692,770 1,108,433

2 0 0 0 0 0 5.29 0 79,365 2,380,950 2,380,950 3,809,520 5,248,590 910,550 2,565,313 PDZ2Gi (with realignment) 3 0 1.45 0 7,846,200 0 1.45 0 29,060 1,569,240 9,415,440 15,064,704 20,313,294 2,184,312 6,060,212

1 0 0 0 0 0 5.29 0 52,907 899,419 899,419 1,439,070 1,439,070 692,770 1,108,433

2 0 5.29 0.00 21,424,500 0 5.29 0 2,380,950 23,805,450 38,088,720 39,527,790 6,411,001 10,257,602 7,103,771 PDZ2Gi (without realignment) 3 0 0.00 0.00 0.00 0 5.29 0 5,713,200 5,713,200 9,141,120 48,668,910 832,194 1,331,510 7,935,965

1 0 0 0 0 0 0.88 0 8,800 123,200 123,200 197,120 197,120 115,228 184,365

2 0 0.88 0 3,564,000 0 0.88 0 13,200 396,000 3,960,000 6,336,000 6,533,120 1,066,452 1,890,688 PDZ2G (River Burn outfall) 3 0 0 0 0 0 0.88 0 17,600 950,400 950,400 1,520,640 8,053,760 138,437 2,112,187



Length (km) Length (km) Policy unit Epoch

B L G

Cost (£)5

B L G

Cost (£)5 Total cost With

optimism bias (60%)

Cumulative total

PV total

With optimism

bias (60%)

Cumulative PV total

1 0 0 0 0 0 2.02 0 345,508 345,508 552,813 552,813 266,125 425,800 425,800

2 0 0 0 0 0 2.02 0 910,530 910,530 1,456,848 2,009,661 348,215 557,144 982,944

PDZ2G (Overy marshes, with realignment)

3 0 1.67 0 8,991,000 0 1.67 0 1,798,200 10,789,200 17,262,720 19,272,381 2,503,014 4,004,823 4,987,767

1 0 0 0 0 0 2.03 0 345,508 345,508 552,813 552,813 266,125 425,800 425,800

2 0 2.032 0 8,231,220 0 2.03 0 914,580 9,145,800 14,633,280 15,186,093 2,463,019 3,940,830 2,729,144

PDZ2G (Overy marshes, without realignment))

3 0 0 0 0 0. 2.03 0 2,194,992 2,194,992 3,511,987 18,698,080 319,726 511,562 3,048,870

1 0 0 0 0 0 1.19 0 202,640 202,640 324,224 324,224 156,082 249,731 249,731

2 0 1.19 0 4,827,600 0 1.19 0 536,400 5,364,000 8,582,400 8,906,624 1,444,557 2,311,292 2,561,023 PDZ 2H

3 0 0 0 0 0 1.19 0 1,287,360 1,287,360 2,059,776 10,966,400 187,519 300,030 2,861,053

1 0 0 0 0 0 0 0 0 0 0 0 0 0 0

2 0 0 0 0 0 0 1 450,000 450,000 720,000 720,000 172,094 275,350 275,350 PDZ2I (dunes)

3 0 0 0 0 0 0 1 810,000 810,000 1,296,000 2,016,000 117,986 188,777 464,128




B L G

Cost (£)5

B L G


optimism bias (60%)

Cumulative total

PV total

With optimism

bias (60%)

Cumulative PV total

1 0 0 0.7 419,400 0 0.11 0.7 138,210 557,610 892,176 892,176 356,791 570,866 570,866

2 0 0.11 0.7 1,090,800 0 0.11 0.7 365,985 1,456,785 2,330,856 3,223,032 424,858 679,772 1,250,638 PDZ2I (hard defences)

3 0 0 0.7 838,800 0 0.11 0.7 878,364 1,717,164 2,747,462 5,970,494 259,578 415,325 1,665,963

1 0 0 0 0 0 1.79 0 303,790 303,790 486,064 486,064 233,992 374,387 374,387

2 0 1.787 0 7,237,350 0 1.79 0 804,150 8,041,500 12,866,400 13,352,464 2,165,624 3,464,999 3,839,386 PDZ 2J

3 0 0 0 0 0 1.79 0 1,929,960 1,929,960 3,087,936 16,440,400 281,121 449,794 4,289,179



Length (km) Length (km) Policy unit

Epoch

B L G Cost (£)5

B L G

Cost (£)5

Total cost


Cumulative total

PV total With

optimism bias (60%)

Cumulative PV total

1 0 0 0 0 0 0.78 0 132,600 132,600 212,160 212,160 102,134 163,415 163,415

2 0 0.78 0 3,159,000 0 0.78 0 351,000 3,510,000 5,616,000 5,828,160 945,264 1,512,422 1,675,837 PDZ2K

3 0 0 0 0 0 0.78 0 842,400 842,400 1,347,840 7,176,000 122,705 196,329 1,872,166

1 0 0 0 0 0 0.88 0 8,800 123,200 123,200 197,120 197,120 115,228 184,365

2 0 0.88 0 3,564,000.00 0 0.88 0 13,200 396,000 3,960,000 6,336,000 6,533,120 1,066,452 1,890,688 PDZ2L

3 0 0 0 0 0 0.88 0 17,600 950,400 950,400 1,520,640 8,053,760 138,437 2,112,187

1 0 0 0 0 0 0.32 0 54,910 54,910 87,856 87,856 42,294 67,670 67,670

2 0 0.32 0 1,308,150 0 0.32 0 145,350 1,453,500 2,325,600 2,413,456 391,436 626,298 693,968

PDZ3A (River Stiffkey outfall) 3 0 0 0 0 0 0.32 0 348,840 348,840 558,144 2,971,600 50,813 81,300 775,269

1 0 0 0 0 0 7 01.1 11,650 163,100 163,100 260,960 260,960 152,546 152,546

2 0 1.17 0 4,718,250 0 7 01.1 17,475 524,250 5,242,500 8,388,000 8,648,960 1,411,837 1,564,383 PDZ3A (Morston)

3 0 0.00 0 0 0 7 01.1 23,300 1,258,200 1,258,200 2,013,120 10,662,080 183,271 1,747,655

1 0 0 0 0 0 4.21 0 714,833 714,833 1,143,733 1,143,733 550,595 880,951 880,951

2 0 0.37 0 1,506,600 0 0.2 0 87,750 1,594,350 2,550,960 3,694,693 657,652 1,052,243 1,933,194 PDZ3A 3

3 0 0 0 0 0 0.2 0 210,600 210,600 336,960 4,031,653 30,676 49,082 1,982,276




B L G

Cost (£)5

B L G


optimism bias (60%)

Cumulative total

PV total

With optimism

bias (60%)

Cumulative PV total

1 0 0 0 0 0 0.22 0 37,315 37,315 59,704 59,704 28,742 45,987 45,987

2 0 0.22 0 888,975 0 0.22 0 98,775 987,750 1,580,400 1,640,104 266,007 425,611 471,598

PDZ3A (River Glaven outfall) 3 0 0 0 0 0 0.22 0 237,060 237,060 379,296 2,019,400 34,531 55,249 526,847

1 0 0 0 0 0 0.51 0 86,020 86,020 137,632 137,632 66,256 106,010 106,010

2 0 0.51 0 2,047,680 0 0.51 0 227,700 2,275,380 3,640,608 3,778,240 612,794 980,470 1,086,480 PDZ3A (Cley)

3 0 0 0 0 0 0.51 0 546,480 546,480 874,368 4,652,608 79,601 127,362 1,213,842

1 0 0 0 0 0 1.81 0 307,190 307,190 491,504 491,504 236,611 378,577 378,577

2 0 0 0 0 0 1.81 0 813,150 813,150 1,301,040 1,792,544 310,974 497,558 876,135

PDZ 3A (Cley marshes, with realignment)

3 0 2.33 0 12,555,000 0 2.33 0 2,511,000 15,066,000 24,105,600 25,898,144 3,495,200 5,592,320 6,468,456

1 0 0 0 0 0 1.81 0 307,190 307,190 491,504 491,504 236,611 378,577 378,577

2 0 1.807 0 7,318,350 0 1.807 0 813,150 8,131,500 13,010,400 13,501,904 2,189,862 3,503,779 2,426,473

PDZ 3A (Cley marshes, without realignment)

3 0 0 0 0 0 1.807 0 1,951,560 1,951,560 3,122,496 16,624,400 284,267 454,827 2,710,740

90




B L G

Cost (£)5

B L G


optimism bias (60%)

Cumulative total

PV total

With optimism

bias (60%)

Cumulative PV total

1 0 0 0 0 0 1.42 0 240,550 240,550 384,880 384,880 185,282 296,451 296,451

2 0 1.42 0 5,730,750 0 1.42 0 636,750 6,367,500 10,188,000 10,572,880 1,714,806 2,743,689 3,040,140 PDZ3C

3 0 0 0 0 0 1.42 0 1,528,200 1,528,200 2,445,120 13,018,000 222,600 356,160 3,396,300

1 0 0 0 0 0 0 0 0 0 0 0 0 0 0

2 0 0 0 0 0 0 4.98 224,145 224,145 358,632 358,632 96,173 153,877 153,877 PDZ3D

3 0 0 0 0 0 0 4.98 373,575 373,575 597,720 956,352 69,481 111,170 265,047


Table H6 Supporting economic data – defence cost calculations for each super-frontage

Replacement Maintenance Total cost (£) PV costs (£) Length (km) Length (km) Policy unit Epoch

B L G Cost (£)5

B L G Cost (£)5 Total cost


Cumulative total

PV total With

optimism bias (60%)

Cumulative PV total

1 0 0 0.42 252,600 0 3.508 1.71 886,584 1,139,184 1,822,694 1,822,694 8,336,585 1,333,853 1,333,854 2 0 1.31 0.42 6,204,150 0 2.968 0.42 1,522,800 7,186,950 11,499,120 13,321,814 2,039,478 3,263,165 4,597,018

SF1 with

conditional realignments 3 0 1.69 0.42 9,504,900 0 3 0.42 3,575,610 13,080,510 20,928,816 34,250,630 2,855,027 4,568,043 9,165,063

1 0 0.00 0 252,600 0 3.508 1.71 621,304 1,139,184 1,822,694 1,822,694 833,658 1,333,854 1,333,854 2 0 2.97 0 12,919,050 0 2.968 0.42 801,570 7,186,950 22,242,960 24,065,654 3,763,438 6,021,501 7,355,355

SF1 without

conditional realignments 3 0 0.05 0 648,900 0 3.018 0.42 1,837,570 4,243,950 6,790,320 30,855,974 650,423 1,040,677 8,396,033

1 0 0 0.9 539,400 0 27 0.9 3,428,998 5,195,160 7,526,905 8,312,256 4,991,690 5,711,644 6,265,581 2 0 14.15 0.9 58,096,350 0 21.35 1.9 6,887,055 56,711,115 100,365,714 115,909,770 41,770,150 28,145,466 36,237,119

SF2 with

conditional realignments

3 0 3.12 0.9 17,916,000 0 17.16 1.9 15663,644 30,374,124 53,607,854 152,192,768 51,761,196 10,129,740 47,843,571

1 0 0 0.9 539,400 0 27 0.9 3,428,998 5,195,160 7,526,905 8,312,256 4,991,690 5,711,644 6,265,581 2 0 19.7574 0.9 80,835,480 0 20.62 1.9 10,131,705 90,967,185 145,547,496 155,914,985 24,632,946 39,412,712 40,382,775

SF2 without


3 0 0 0.9 1,078,800 0 20.62 1.9 24,045,012 25,123,812 40,198,099 196,113,084 3,670,814 5,873,301 45,396,157

1 0 0 0 0 0 3.96 0 671,075 671,075 1,073,720 1,073,720 516,891 827,025 827,025 2 0 2.15 0 8,667,405 0 3.96 4.98 2,000,520 10,667,925 17,068,680 18,142,400 3,000,754 4,801,205 5,628,230

SF3 with


3 0 2.33 0 12,555,000 0 4.48 4.98 5,196,315 17,751,315 28,402,104 46,544,504 3,901,413 6,242,261 11,870,492


Replacement Maintenance Total cost (£) PV costs (£) Length (km) Length (km) Policy unit Epoch

B L G Cost (£)5

B L G Cost (£)5 Total cost


Cumulative total

PV total With

optimism bias (60%)

Cumulative PV total

1 0 0 0 0 0 3.96 0 671,075 671,075 1,073,720 1,073,720 516,891 827,025 827,025 2 0 6 0 23,518,755 0 6 5 2,757,870 26,276,625 42,042,600 44,608,869 7,340,567 11,744,906 11,370,113

SF3 without


3 0 0 0 0 0 6 5 6,454,515 6,454,515 10,327,224 54,936,093 955,240 1,528,385 12,617,975

appendix h economic appraisal - eacg h - economic appraisal.pdf · north norfolk smp2 - h 4 -...

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